The present invention relates to an assembly line as defined in the preamble of claim 1.
In prior arc, an electronics industry assembly line is known which comprises a number of pallets fitted to receive components of a product co be assembled. Each pallet is provided with an RF-tag carrying stored information about the product co be assembled Furthermore, the assembly line comprises a conveyor constructed in the shape of an endless loop and fitted to convey the pallets. Moreover, the assembly line comprises assembly work stations disposed along the main conveyor so that they can receive a pallet from the main conveyor and carry out assembly operations on the product on the pallet within the framework of the working area of the work station. Each assembly work station is provided with a reading device for reading the contents of the RF-tag before carrying out the assembly operation. Based on the data read from the RF-tag, a data processing device controls the assembly work station, causing it to perform a number of predetermined assembly operations, such as placing a component on the product and/or on the pallet. This type of flexible modular assembly lines are manufactured e.g. by Prodel Technologies, Carlepont, France. The working principles and details of the assembly line are described e.g. in Prodel patents U.S. Pat. Nos. 4,519,491, 4,646,245, 4,787,496 and 4,832,171 etc.
In a known assembly line system like this, an example of which is illustrated by the diagram in FIG. 1, the supply of components to the working area of the robot at the work station at the middle of the line is implemented by having a number of components carried on pallets on a storage conveyor A parallel co the main conveyor, and when a given component is needed, the entire pallet is moved by means of a transverse transfer gear B into the picking area of the robot.
The problem is chat the robot or, in the case of a manual work station, the worker has a specific limited working area, where the pallets cake up a large space if they are brought there. The working area of a conventional robot can only accommodate a very limited number of pallets and their feed devices, e.g. only two as in FIG. 1. If there is a larger number of component variants to be assembled by the same robot, it is difficult to supply them on pallets to the working area of the robot. In series production with small series there may be different production lots simultaneously on the assembly line, so such a situation is likely c develop in-process inventories and buffers. Moreover, a change of series cannot be flexibly accomplished without the operator""s intervention.
The object of the present invention is to eliminate the drawbacks described above.
The assembly line of the invention is characterised by what is presented in claim 1.
According to the invention, the assembly line comprises an automatic storage system disposed in the vicinity of the assembly work station, said automatic storage system comprising a number of storage devices, transfer means disposed between the storage devices and the assembly work station for supplying a predetermined component from a predetermined storage location co the working area of the assembly work station on the basis of data read from the RF-tag.
The invention provides the advantage that the space available in the working area of the assembly work station constitutes no limitation of the number of components chat can be assembled in the work station. The supply of components to the working area does not require a buffer nor is one formed in the working area as the components are fetched from the storage device as necessary. A large amount of different components can be supplied to and handled by the same work station.
Furthermore, the work station allows very small production series. A change of series requires no action on the operator""s part.
I an embodiment of the assembly line, the storage device comprises a number of pallets placed over each other, each carrying a number of components. The transfer means comprise a component conveyor extending from the vicinity of the storage device to the working area of the assembly work station, and a manipulation arm or equivalent provided with a gripping device for gripping a component on a pallet and moving it onto the component conveyor.
In an embodiment of the assembly line, the assembly line comprises a carriage fitted to receive and support the component; and a guide for forming a track for the carriage.
In an embodiment of the assembly line, the assembly line work station is a manual work station for a worker for the execution of manual assembly operations on a product on a pallet.
In an embodiment of the assembly line, the work station is an assembly robot cell fitted to perform an automatic assembly operation on a product on a pallet.
In an embodiment of the assembly line, the assembly line comprises a side conveyor disposed in the area of the assembly work station and branching out from the main conveyor co receive a pallet from the main conveyor and convey it to the working area of the work station for an assembly operation and deliver the pallet back to the main conveyor.
In an embodiment of the assembly line, the assembly robot cell comprises a robot provided with a gripping device designed to grip a component on a carriage in the working area and move it from the carriage to the product being assembled on the pallet.
In an embodiment of the assembly line, the storage device comprises a shelf means provided with supporters on which the pallets are arranged one over the ocher and an elevating gear for successively moving the supporters in a vertical direction so that the pallets are moved upwards, and for moving the supporters for an upper and a lower pallet placed successively over each other with respect to each other when facing the manipulation arm so as to form an interspace between the upper and lower pallet into which the manipulation arm together with the gripping device can be inserted in order to pick up a component from the lower pallet.
In an embodiment of the assembly line, the assembly work station has been organised to do assembly work consisting of mounting a component having several variants on a product. The automatic storage system comprises a storage device for each variant, so that the pallets of each different storage device carry the same variant.